Dynamoelectric machine



Junefi, 1967 L. J. RAVE-IR DYNAMOELECTRIC MACHINE '7 Sheets-Sheet 1Original Filed Sept. 28, 1961 INVENTOR. 1 011119 f. Ra re) 1916'ATTOR/Vi) 7 Sheets-Sheet 2 Original Filed Sept. 28, 1961 llllllllfmIIIHHI MINNIQ 3 I N mm m m T V N W a I w n Ilium J R W s on H lws m Q nw l v m It n m H June 6, 1967 L. J. RAVER DYNAMOELECTRIC MACHINE '7Sheets-Sheet 3 Original Filed Sept. 28. 1961 {lllmlllk INVENTOR low: IRel er June 6, 1967 L. J. RAVER DYNAMOELECTR I C MACHINE Original FiledSept. 28, 1961 7 Sheets-Sheet 4 INVENTOR.

Z 0111': J /?a yer A)! ATTORNiY June 6, 1967 L. J. RAVEIR DYNAMOELECTRICMACHINE Original Filed Sept. 28, 1961 "7 Sheets-Sheet 5 INVENTOR 011134/. fiat er GIRlW HIS A77'0R/Viy June 6, 1967 J RAVER DYNAMOELECTRICMACHINE 7 Sheets-Sheet (:2

Original Filed Sept. 28, 1961 an. 2 ma M J .s z a a Z BY am 191.9ATY'OR/Viy June 6, 1967 L. J. RAVER DYNAMOELECTRIC MACHINE 7Sheets-Sheet 7 Orlginal Filed Sept. 28, 1961 Rr 3 N W04! mRv .smk wnw 1wMk 3% MR \m United States Patent 3,324,383 DYNAMOELECTRIC MACHINE Louis.I. Raver, Anderson, Ind, assignor to General Motors Corporation,Detroit, Mich, a corporation of Delaware Original application Sept. 28,1961, Ser. No. 141,448, now Patent No. 3,271,601, dated Sept. 6, 1966.Divided and this application Dec. 13, 1965, Ser. No. 525,276

2 (Claims. (Cl. 32273) vehicle manufacturer and these various parts aresecured in position and wired together by the motor vehiclemanufacturer.

In contrast to the above noted common practice of wiring up severalelements to make a power system, it is an object of this invention toprovide a single unit generator which has both a built-in regulator andbuilt-in diodes for providing a direct current output. With thisarrangement, it is only necessary to mount the power unit in place onthe motor vehicle, connect it with the driving means and connect theoutput terminals of the unit to the load terminals of the vehicle to putthe unit into operation.

Another object of this invention is to provide a generator with abuilt-in transistor voltage regulator.

Still another object of this invention is to provide a power unit thatis comprised of an enclosed generator having an enclosed built-intransistor voltage regulator. This object is of particular importancewhere the vehicle operates in a dusty atmosphere such as on earth movingequipment.

A further object of this invention is to provide a power unit that iscomprised of a generator having a regulator which is supported by thefan shroud of the generator.

Another object of this invention is to provide a brushless alternatingcurrent generator that comprises a field winding and a fixed statortogether with a rotor that rotates between the field winding and stator,the arrangement being such that the core of the field winding rotateswith the rotor but wherein the field winding remains stationary.

A further object of this invention is to provide an electric powersystem for motor vehicles and the like that includes an alternatingcurrent generator and a transistor regulator, the AC output of thegenerator being rectified to direct current by a first bridge rectifierwhich feeds the DC. loads of the vehicle, there being a second bridgerectifier connected with the AC output of the generator which feedsdirect current to the transistor regulator and also supplies field powerto the field coil of the generator through the regulator.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings, wherein a preferred embodiment of the present invention isclearly shown.

In the drawings:

FIGURE 1 is an end view of a dynamoelectric machine made in accordancewith this invention and looking in the direction of the arrow designatedby reference numeral 1 in FIGURE 2.

3,324,383 Patented June 6, 1967 FIGURE 2 is a side plan view of thedynamoelectric machine illustrated in FIGURE 1.

FIGURE 3 is a sectional view taken along lines 33 of FIGURE 2 andillustrating the opposite end of the dynamoelectric machine from thatshown in FIGURE 1.

FIGURE 4 is a sectional view taken along line 44 of FIGURE 1.

FIGURE 5 is an enlarged sectional view taken along line 55 of FIGURE 1.

FIGURE 6 is a schematic electric circuit diagram of a power unit made inaccordance with this invention.

FIGURE 7 is a sectional view taken along line 7-7 of FIGURE 4.

FIGURE 8 is a sectional view taken along line 8-8 of FIGURE 4.

FIGURE 9 is an end view of a subassembly which forms a part of the powerunit illustrated in FIGURE 4.

FIGURE 10 is a sectional View taken along line 1010 of FIGURE 9.

Referring now to the drawings and more particularly to FIGURE 4, thepower unit of this invention comprises an end frame generally designatedby reference numeral 10 and a second end frame assembly generallydesignated by reference numeral 12. The end frame assemblies 10 and 12are held together by suitable bolts not illustrated and it is seen thatthe end frame 10 has an end wall 14 and an annular wall 16. The endframe 10 may be formed of a suitable metal material such as die castaluminum and it is seen that the annular wall 16 has an annular recess18.

The end frame assembly 12 comprises a frame memher having an annularwall 20 and an end wall 22. This end frame is likewise formed of metalmaterial and may be formed of die cast aluminum. It is seen that theannular wall 20 has an annular recess 24 which receives an end of theannular wall 16 of end frame 10. An O-ring seal 26 is compressed betweenthe walls 16 and 20. The end wall 14 is imperforate except for a bearingopening and end wall 22 is also imperforate except for certain coveredopenings and when the end frames are secured together a sealed chamber28 is provided which encloses the elements of the generator. Thegenerator thus may be referred to as a totally enclosed generator as thechamber 28 is completely enclosed so that dust, dirt and the like cannotenter this chamber. The end frame assembly 12 is better illustrated inFIGURES 9 and 10 and it is seen that the annular wall 20 is providedwith radially extending ribs 30 and the radially extending bosses 32.The radially extending bosses 32 have tapped holes 34 and are used tosecure a fan shroud in place as will become more readily apparenthereinafter.

The end wall 22 of end frame 12 has an annular opening 36 which isclosed by a metal heat sink block 38. The heat sink block 38 is formedof a good heat conducting material such as die cast aluminum and hasthree threaded openings which receive the diodes 40, 42 and 44. Thediodes 40, 42 and 44 are of the pn junction semiconductor type andpreferably of the silicon type. Each of the diodes has an outer metalcase formed with threads that match the threaded openings in the heatsink 38. The diodes each have a hexagonal head and the diode 40 has arelatively stiff self-supporting terminal 40a which projects into thechamber 28 as is clearly apparent from FIGURE 4. In a similar fashion,the diode 42 is provided with a relatively stiff metal terminal 42a andthe diode 44 has the same type of terminal 44a. The rectifying junctionfor the diodes 40 through 44- has one side thereof connected with themetal case of the diodes and the other side connected with theprojecting terminals.

The heat sink 38 is secured to the end wall 12 by a plurality offasteners 46 which are electrically insulated QB from the heat sink 38.The heat sink member 38 is electrically insulated from the end wall 22by an insulating gasket 48. It is seen that the heat sink member 88 hasan integral section 50 formed with a slot 52 which receives the head ofa terminal stud 54. The terminal stud 54 has a threaded sectionreceiving the nuts 56 and this terminal stud passes through a slot 58formed in a fan shroud which is generally designated by referencenumeral '59. The terminal stud 54 is electrically insulated from themetal fan shroud 59 but is electrically connected with the section 50 ofthe heat sink 38. It therefore is seen that the terminal stud 54 will beat the same electrical potential as one side of the diodes 40 through 44and this terminal stud 54 therefore is one DC output terminal of thepower unit.

The annular wall 20 as is better illustrated in FIG- URES 9 and hasthreaded openings which respectively receive the diodes 60, 62 and 64.It can be seen that the diode openings extend radially of the annularwall and that the diodes have relatively stilf terminals 60a, 62a and64a. The diodes 60, 62 and 64 are the same as the diodes 40, 42 and 44in that they have outer metal case-s formed with threads and haveprojecting terminals. The rectifying junction within the diodes 60, 62and 64 is reversed, however, from the rectifying junction within diodes40, 42 and 44 so that the annular portion 20 will be at a differentelectrical potential than the heat sink 38. The annular section 20 isprovided with a threaded opening 66 which receives the terminal stud 68.The terminal stud 68 is threaded and carries a pair of nuts. Theterminal stud 68 will be at the same electrical potential as the annularsection 20 of the end frame 1-2 and willbe at the same electricalpotential as the case side of the diodes 60, 62 and 64. It thus is seenthat direct current can be taken across the terminal studs 54 and 68with the terminal stud 68 being the grounded terminal.

The end wall 22 of the end frame assembly 12 carries a field coilassembly which includes the tubular member 70 which' is formed of amagnetic material such as steel. The tubular member 70 is held to theend wall 22 by one or more fasteners 72 which are threaded into threadedopenings in the member 70. The member 70 carries a metal coil form 74which is welded or otherwise secured thereto and this coil form supportsa field winding 76 made up of a plurality of turns of wire. One side ofthe field winding 76 is connected with the conductor 78 and thisconductor as can be seen from FIGURE 4 passes through an opening formedin the member 70. The field coil 76 is insulated from the metal coilform 74 by a sheet of thin insulating material which is not illustrated.One side ofthis field coil however is connected with the metal coil form74 and this may be accomplished by leaving a part of the coil form '74uncovered by insulation when beginning the winding of the field coil 76and winding some of the field coil wires directly against the coil form74. This length of wire must, of course, have its insulation strippedoff so that one side of the coil winding 76 will be connected with themetal coil form 74. The field coil 76 is thus electrically connectedbetween the lead wire 78 and the metal coil form 74. The metal coil form74 of course is at ground potential and is at the same potential as theterminal stud 68.

seen'that the power unit of this invention has a stator assembly whichis generally designated by reference numeral 86. This stator assemblyincludes the laminated stator iron 88 which fits within the annularrecess 18 of the annular wall 16 and which is clamped between theannular walls 16 and 20. The stator laminations 18 carry a three phaseY-connected stator winding 90 which is wound in slots in the stator iron88.

The end wall 22 of the end frame assembly 12 is provided with an openingwhich receives a ball bearing assembly 92. The inner race of the ballbearing of this assembly is fixed to a shaft 94 and it is seen that theball bearing assembly is sealed by means of a seal 96. In addition, oilseals 98 and 100 are provided to maintain the balls of the ball bearingassembly lubricated. The sealing, of course, maintains the chamber 28sealed so that dirt and the like cannot enter this chamber.

The end wall 14 is likewise provided with a ball bearing assembly whichis generally designated by reference numeral 102. The inner race of theball bearing of this assembly is fitted to the shaft 94 and it is seenthat this ball bearing assembly is sealed by means of the seals 104, 106and 108. The seals of the ball bearing assembly 102 thus also serve tomaintain the chamber 28 sealed from dust and other materials that wouldbe detrimental to the working parts of the generator.

Fitted on the shaft 94 is an annular core member 110 which is formed ofa magnetic material such as steel. The core member 110 serves as a corefor the field winding 76 and also extends coextensively with the annularmember 70.

The shaft 94 carries a pole member 112 which has axially projectingcircumferentially spaced fingers 112a. A second pole member 114 isprovided which has axially extending circumferentially spaced fingers114a that interleave with the fingers 112a of the pole member 112. Thepole member 114 is secured to the pole member 112 by means of an annularmember 116. The annular member 116 is formed of a non-magnetic materialsuch as cast manganese bronze and is brazed to the pole members 112 and114. It thus is seen that the pole members 112 and 114 will rotate withthe shaft 94 as will the annular magnetic member 110. It is seen thatthe annular magnetic member 110 is secured to the pole member 112 by oneor more fasteners 118.

It will be appreciated by those skilled in the art that when the fieldcoil winding 76 is fed with direct current an alternating current willbe developed in the stator winding 90 as the pole members 112 and 114rotate between the field winding 76 and the stator assembly 86. The polemembers 112 and 114 and, the annular magnetic member 110 and the shaft94 actually make up a rotor assembly. It is seen that the shaft 94 isconnected with a pulley 120 which may be belt driven and that this shaftalso is connected with a fan 122 having blades 124. When the pulley 120is driven and the field winding 76 is supplied with direct current, analternating current is generated in the three phase Y-connected statorwinding 90.

Referring now more particularly to FIGURES 1, 5 and 9, it is seen thatthe end wall 22 of end frame assembly 12 carries a terminal board 126which is formed of insulating material. The terminal board 126 issecured to the end wall 22 by fasteners 128 and is positioned inalignment with an opening 130 formed in the end wall 22. This opening130 is closed by a cover plate 132 which is fixed to the end wall 22 bythe fasteners 134.

The terminal plate 126 carries terminals 136, 138, and 142. Theterminals 136 through 142 are substantially identical and one of theterminals 136 is shown in detail in the sectional view of FIGURE 5. Thisterminal like the other terminals has a head section that is rivetedover and has a threaded shank section which receives nuts and terminals.The terminal stud 136 is connected with a lead wire 144 that comes fromone of the phase windings of the stator winding 90. This terminal stud136 as is best illustrated in FIGURE 5 is also connected with a I leadwire 146 which passes through a grommet 148 fitductor 150. The terminalstud 140 is connected with a lead wire 152 which passes through therubber grommet 154. The terminal stud 142 is connected with anotherphase winding of the stator winding 90 by the lead wire 156 and thisterminal stud is connected with lead wire 158 that passes through therubber grommet 16-8. The

terminal 138 is connected with the lead wire 78 coming from one side ofthe field winding 76. The terminal 138 is also connected with a leadwire 162 which passes vnected with a conductor member 170 and thisconductor member is connected with the terminals 42a and 62a of .diodes42 and 62 via the lead wires 172 and 174. The

terminal stud 142 is connected with a conductor member 176 and thisconductor member is connected with the projecting terminals 44a and 64aof diodes 44 and 64 via lead wires 178 and 180'. It can be seen from theforegoing that the physical arrangement of the power unit is such thatthe diodes 40, 42, 44, 68, 62 and 64 are connected in a three phase fullwave bridge rectifier with the phase windings of the stator winding 90.It also can be seen that the output terminals of this bridge rectifierare the terminal 54 and the grounded terminal 68. This is depicted inthe schematic circuit diagram of FIGURE 6. Referring now moreparticularly to FIGURES 2 and 4, it is seen that the fan shroud 59encircles the fan 122 and has an end wall 181 and an annular wall 182.The end wall 180 is formed with a plurality of air inlet openings 184 ascan readily be seen from FIGURES 1 and 4. The annular section 182 of thefan shroud 59 engages the threaded bosses 32 and fasteners 186 are usedto secure the fan shroud in place on the end frame assembly 12. Thesefasteners 186 fit within the threaded openings 34 formed within thebosses 32. It is pointed out that the annular section 182 of the fanshroud is spaced sufficiently from the periphery of the end frameassembly 12 to permit air to exit between the fan shroud and the annularsection of the end frame assembly 12. This air will exit over the heatradiating ribs and will pass in contact with the heads of diodes 60, 62and 64.

The end Wall 181 of the 'fan shroud 59 carries a plurality of firstmetal tubular members 188 and a plurality of second metal tubularmembers 190 which are shorter than the metal tubular members 188. Thetubular members 188 and 198 are welded to the end Wall 181 or otherwisesecured to this end wall. The tubular members 190 serveto support aprinted circuit board 192 which is formed of suitable electricinsulating material. This printed circuit board 192 is secured to theposts 190 by fasteners which pass through the printed circuit board andare .threaded into the tubular supports or posts 190. The

printed circuit board, as is described hereinafter, supports electricalcomponents that form a transistor regulator.

The projecting posts 188 serve to support a cover memher 196 which withthe end wall 181 of the fan shroud '59 forms a sealed annularcompartment 198 that houses the transistor regulator. The cover member196 is secured to the posts 188 by the fasteners 280' which are threadedinto the posts 188. It is seen that the cover memher 196 is annular inconfiguration and generally cupshaped. The fasteners 200 also serve tofix the cover a plate 196 with respect to the end wall 181 of the fanshroud 59. It can be seen from FIGURE 4 that suitable gaskets areinterposed between the cover plate 196 and the fanshroud 59 to form acompletely sealed compartment for the transistor regulator.

Referring now more particularly to FIGURES 7 and 8, it can be seen thatthe printed circuit board 192 carries a plurality of electricalcomponents and printed circuit conductors which are formed on theprinted circuit board 192 in any well-known manner. In FIGURE 7, it isseen that the printed circuit board 192 carries printed circuitconductors 284, 206, 208 and 210. Passing through these printed circuitconductors and electrically connected therewith are the terminal studs212, 214, 216 and 213. The heads of these terminal studs are rivetedover, as is seen from FIGURE 8, and the studs have threaded sectionswhich receive the nuts shown in FIGURE 7. The terminal stud 218 isconnected with the lead wire 162 coming from the terminal plate 126 andthus is connected to one side of the field winding 76 of thedynamoelectric machine. The terminal stud 212 which is connected withprinted circuit conductor 204 is connected with the lead wire 158. In asimilar fashion, the terminal stud 214 is connected with lead wire 152and the terminal stud 216 is connected with the lead wire 146. From aninspection of FIGURES 5 and 7, it is seen that as the lead wires 146,162, 152 and 158 emerge from the cover plate 132 they then pass througha rubber grommet 238' fitted within an opening formed in the annularWall 182 of the fan shroud 68. The lead wires then pass through a covermember 232 which is secured to the fan shroud by the fasteners 234. Thelead wires then pass through one or more gasket members 236 and thenpass into the sealed chamber 198 where they are connected respectivelywith the terminals 212, 214, 216 and 218. The cover plate I 232, ofcourse, will protect the lead wires and it is seen that these lead wiresconnect parts contained within the -chamber 198 and parts carried by theterminal plate 126 located in chamber 28, and in making theseconnections the parts are still maintained sealed from the atmosphere.It is also seen that by this connecting means, the printed circuitconductors 204, 206 and 208 are con nected with the phase windings ofthe stator winding 90.

The printed circuit conductor 210 is connected with the field winding 76of the power unit.

Referring now more particularly to FIGURES 7 and 8, it is seen that theprinted circuit board 192 supports a pair of diodes 248 and 242. Theterminal 240a of diode 240 is connected with printed circuit conductor204. This connection is made by passing the terminal 240a throughopenings in the printed circuit board and printed circuit conductor 204and then soldering or otherwise securing this terminal to the printedcircuit conductor 284. In a similar fashion, the terminal 242a of diode242 is connected with the printed circuit conductor 286. The otherterminals 2441b and 242b pass through an opening in the printed circuitboard 192 and are connected with a I printed circuit conductor 244 at246. The printed circuit conductor 244 is actually at ground potentialdue to the fact that it is connected with one of the metal posts 190 bya fastener 248 which also serves to hold the printed circuit boardassembly in place. The printed circuit conductor 244 is connected withlead wire 250a of a diode 250. The other terminal lead 250 b and aterminal lead 252]) of diode 252 pass through the printed circuit boardand are connected with the printed circuit conductor 288.

The terminal 252a of diode 252 is connected with a printed circuitconductor 254.

Another diode 256 has one terminal connected with the printed circuitconductor 206 and has its opposite terminal 2561; connected with theprinted circuit conductor 254. Another diode 258 is provided and thisdiode is connected between printed circuit conductors 204 and 254. Adiode 260 is provided which has one terminal side 260a passing throughthe printed circuit board and connected with the printed circuitconductor 254. Terminal 26% of the diode 268 is connected with theprinted circuit conductor 262. The printed circuit conductor 262 is alsoconnected to the terminal lead wire of a resistor 264, the opposite sideof this resistor being connected With the printed circuit conductor 266.A resistor 268 is provided and this resistor has terminal leadsconnected respectively with printed circuit conductors 266 and 270.Another resistor 272 has terminal leads connected between printedcircuit conductor 270 and printed circuit conductor 274. Still anotherresistor 276 has terminal leads connected between circuit conductor 274and printed circuit conductor 278.

The printed circuit conductors 262, 266, 270, 274 and 278 engageferrule-like connectors 262a, 266a, 270a, 274a and 278a. The ferruleconnector 270a is shown in FIG- URE 4 of the drawings and it is seenthat it passes through the printed circuit board 192. The otherconnectors 262a, 266a, 274a and 278a are like the ferrule connector270a. Positioned in alignment with these fer- I also serves to connectthe conductor strap 280 to ground potential.

A shorting screw 294 is provided which may be passed selectively throughany of the ferrules 262a, 266a, 270a, 274a and 278a, and then threadedinto one of the threaded openings in the conductor strap 280. Thisconductor screw 294 thus serves as a voltage adjustment means foradjusting the voltage setting of the transistor voltage regulator.

The printed circuit conductor 278 which is connected with one side ofresistor 276 is also connected to one side of a resistor 300 by virtueof the terminal 300a which is connected with the printed circuitconductor 278. The opposite side of resistor 300 is connected with theprinted circuit conductor 302 by virtue of its lead wire 3001:.

The printed circuit conductor 302 is connected to one terminal of apotentiometer resistor 304. This connection is made by terminal 304a ofthe potentiometer resistor.

Another terminal 304]) of the potentiometer resistor is connected withthe printed circuit conductor 306. A resistor 308 has one terminal sideconnected with the printed circuit conductor 306 and has its otherterminal side 308a connected with the printed circuit terminal 254. Thethird terminal 304c of the potentiometer resistor 304 is connected witha printed circuit conductor 312.

It can be seen that the top end of the printed circuit conductor 312 isconnected with lead wires. One of these lead wires is the conductor 314aof a capacitor 314 The other conductor connected with printed circuitconductor 312 is the conductor 316a coming from a capacitor 316. Thethird conductor is conductor 318a coming from a Zener diode 318. Theopposite side of capacitor 314 is connected with printed circuitconductor 210 by means of an electrically conductive fastener 320 whichalso serves to fix the capacitor 314 in place on the printed circuitboard. The side of capacitor 316 opposite to terminal side 316a isconnected with printed circuit conductor 254 by its lead wire 316b. Theother terminal 318k of Zener diode 318 is connected with a printedcircuit conductor 324.

The printed circuit conductor 324 is connected with the base electrodeof a transistor 326. The printed circuit conductor 324 is also connectedwith the lead wire 328a of a resistor 328. The other lead Wire 3281) ofresistor 328 is connected with the printed circuit conductor 330. Theprinted circuit co/nducfior 330 is connected with the emitter electrodeof transistor 326, with one side of a resistor 332 and with the leadwire 334a of the diode 334. The collector electrode of transistor 326 isconnected with the printed circuit conductor 346. The printed circuitconductor 346 is connected to one side of a re-.

sistor 348, the opposite side of this resistor being connected withprinted circuit conductor 350. The printed circuit conductor 350 is atground potential by virtue of the fastener screw 352 which passes intoone of the tubular posts 190 extending from the shroud 59.

The printed circuit conductor 350 is connected to the terminal lead wire352a of a diode 352. The other terminal lead 35211 of diode 352 isconnected with the printed circuit conductor 210. v

The printed circuit board 192 supports a metal heat sink member which isgenerally designated by reference numeral 360. The metal heat sinkmember 360 is held in place by fasteners 362 and 364 which are threadedinto suitable openings formed in the heat sink member. The fastener 364passes through the printed circuit conductor 210 and therefore serves toelectrically connect the metal heat sink member 360 'with the printedcircuit conductor 210.

The metal heat sink member 360 supports a transistor 366 of the pnptype. The metal case of this transistor is the collector electrode andtherefore it is seen that the collector electrode of the transistor isconnected with the printed circuit conduct-or 210 via the heat sinkmemher 360. The transistor 366 is held in place on the metal heat sinkmember by fasteners 368 which are threaded into suitable threadedopenings in the heat sink member. The base electrode of transistor 366is connected to printed circuit conductor 346 at 370. The emitter electrode of transistor 366 is connected with the printed circuit conductor372 at point 374. The printed circuit conductor 372 is connected withthe stud end 376 of the diode 334.

It is pointed out that all of the components of the transistor regulatorare supported by the printed circuit board 192 which is disposed withinthe cover member 196 and in the chamber 198 formed by the cover memberand the end wall 181 of the fan shroud. It is also seen from theforegoing description that the elements of the generator are enclosed ina sealed compartment 28 whereas the elements of the transistor regulatorare enclosed in the sealed chamber 198 and that these two parts of thepower unit are connected by the lead wires 162, 158, 152 and 146.

In FIGURE 6; it is seen that a battery 390 is connected between groundand the output terminal 54 of the power unit. It will be appreciatedthat other electrical loads on the motor vehicle can be energizedbetween terminal 54 and ground. When the power unit'of this invention isused on a mot-or vehicle, the engine drives the pulley and initialbuildup of the generator is caused by the permanent magnet 84. As thegenerator builds up, the bridge rectifier comprised of diodes 40, 42,44, 60, 62 and 64 provides power for the electrical loads of the motorvehicle. The other bridge rectifier comprised of diodes 240, 242, 250,252, 256 and 258 provides a DC output voltage which feeds the transistorvoltage regulator and which also feeds the field winding 76 through thetransistor voltage regulator.

The transistor voltage regulator operates to maintain the output voltageappearing across terminals 54 and 68 substantially constant. Theregulator performs this function by switching the transistor 366 on andoffbetween its emitter and the collector electrodes. The circuit for thefield winding 76 may be traced from the junction 254, through resistor332, through diode 334, through the emitter to collect-or circuit oftransistor 366, then through lead Wire 162 and then through the fieldwinding -76 to ground. The conductivity of transistor 366 is controlledby transistor 326 and the conductivity of transistor 326 is controlledby the amount of voltage appearing between junction 254 and ground. Thevoltage sensing element is the Zener diode 318 which is connectedbetween junction 312 and the base electrode of transistor 326. As thevoltage appearing between junction 254 and ground increases, a set ofswitching actions is set into motion to reduce the field current throughfield winding 76. When the voltage between terminal 254 and grounddecreases, an opposite effect is achieved in that field current isincreased through the field winding 76. The output voltage can beadjusted by removing the cover 392 on the cover member 196 and thenshifting the conducting screw 294 to its proper position in one of theferrules.

It is seen from FIGURE 6, that the field winding 76 cannot be initiallyenergized from the battery 390 in order to cause a build-up in generatoroutput voltage. The permanent magnet performs this function and with thearrangement of FIGURE 6, a separate bridge rectifier comprised of therectifiers 240, 242, 250, 252, 256 and 258 provides a sense voltage forthe transistor voltage regulator and also supplies the field current tothe field winding 76.

Referring now more particularly to FIGURE 4, it is seen that as theshaft 94 is driven, the fan 124 rotates. The fan 124 draws air into thepower unit through the air inlet openings 184 and exhausts air throughthe space between the annular portion 182 of the shroud 59* and the endframe assembly 12. The air traversing this path performs very importantcooling functions. First of all, it is seen that air traversing thispath will be moved along the inner surface of the end wall 181 of thefan shroud 59. This flow of air thus serves to cool the transistorregulator which is mounted in the chamber 198. It is also seen that airtraversing the above noted path will pass in contact with the heat sink38 and with the heads of the diodes mounted in this heat sink. Inaddition, as the air is exhausted, the air must pass in contact with theannular wall 20 of the end frame assembly 12 and must also pass incontact with the heads of diodes 62, 64 and 60. It can be seen from theforegoing that although the generator portion of the power unit iscompletely sealed as well as the transistor regulator these elements arestill sutficiently cooled by the arrangement of air cooling that hasbeen provided. In addition, it is seen that the main power diodes areeffectively cooled by the arrangement of this invention. It is also seenthat with the power unit of this invention, a complete power system isprovided in one package that may be mounted on any type of motor vehicleto provide direct current power for the loads of the motor vehicle.

It is pointed out in connection with FIGURE 6 that the diodes 240, 242and 250 could be eliminated if desired since they are in parallel withthe grounding diodes 60, 62 and 64 of the main power bridge rectifier.With such an arrangement, the ground return path for diodes 252, 256 and258 is through diodes 60, 62 and 64 and there is a savings in cost ofthree diodes.

While the embodiments of the present invention as herein disclosed,constitute a preferred form, it is to be understood that other formsmight be adopted.

What is claimed is as follows:

1. An electrical generating system comprising, an alternating currentgenerator having a plurality of output circuits and a field winding, afirst full wave rectifier circuit electrically interconnected with saidalternator output circuits having a bank of diodes having positivepolarity and a bank of diodes of negative polarity and respective directcurrent output circuit means across which an electrical load may beconnected, a second full wave rectifier circuit having at least a bankof positively poled diodes connected to the junction of the positive andnegative polarity diode banks of said first rectifier to cooperate withsaid negative polarity bank of diodes of said first rectifier circuit toprovide a second rectifier circuit having a positive polarity outputcircuit peculiar thereto and a negative polarity output circuit commonwith said first rectifier circuit, a voltage regulator circuit includinga switching transistor having at least emitter and collector electrodesand means for connecting said voltage regulator circuit and the seriescombination of said field winding and said emitter-collector electrodesof said switchingtransistor across said positive and negative polarityoutput circuits of said second rectifier circuit.

2. An electrical generating system comprising, an alternating currentgenerator having a plurality of output circuits and a field winding, afirst full wave rectifier circuit electrically interconnected with saidalternator output circuits having a bank of diodes of positive polarityand a negative polarity and respective direct current output circuitmeans across which an electrical load may be connected, a second fullwave rectifier circuit having at least a bank of positively poled diodesconnected to the junction of the positive and negative polarity diodebanks of said first rectifier to cooperate with said negative polaritybank of diodes of said first rectifier circuit to provide a secondrectifier circuit having a positive polarity output circuit peculiarthereto and a negative polarity output circuit common with said firstrectifier circuit, a voltage regulator circuit including a switchingtransistor having at least base, emitter and collector electrodes, meanfor connecting the series combination of said field winding and saidemitter-collector electrodes of said switching transistor across saidpositive and negative polarity output circuits of said second rectifiercircuit and means connected with said base electrode of said switchingtransistor for controlling the conductance of said transsi-stor inresponse to output voltage magnitude of said generator.

References Cited UNITED STATES PATENTS 2,738,457 3/ 1956- Gilchrist322-28 2,874,346 2/1959 Orvis 322-25 X 3,009,091 11/1961 Hallidy 322-283,031,607 4/1962 Rona 32225 3,173,074 3/1965 Domann 32273 X 3,185,9165/1965 Brewster 322-73 X FOREIGN PATENTS 553,509 12/1956 Belgium.

MILTON O. HIRSHFIELD, Primary Examiner.

J. J. SWARTZ, Assistant Examiner.

1. AN ELECTRICAL GENERATING SYSTEM COMPRISING, AN ALTERNATING CURRENTGENERATOR HAVING A PLURALITY OF OUTPUT CIRCUITS AND A FIELD WINDING, AFIRST FULL WAVE RECITIFIER CIRCUIT ELECTRICALLY INTERCONNECTED WITH SAIDALTERNATOR OUTPUT CIRCUITS HAVING A BANK OF DIODES HAVING POSITIVEPOLARITY AND A BANK OF DIODES OF NEGATIVE POLARITY AND RESPECTIVE DIRECTCURRENT OUTPUT CIRCUIT MEANS ACROSS WHICH AN ELECTRICAL LOAD MAY BECONNECTED, A SECOND FULL WAVE RECTIFIER CIRCUIT HAVING AT LEAST A BANKOF POSITIVELY POLED DIODES CONNECTED TO THE JUNCTION OF THE POSITIVE ANDNEGATIVE POLARITY DIODE BANKS OF SAID FIRST RECIFIER TO COOPERATE WITHSAID NEGATIVE POLARITY BANK OF DIODES OF SAID FIRST RECTIFIER CIRCUIT TOPROVIDE A SECOND RECTIFIER CIRCUIT HAVING A POSITIVE POLARITY OUTPUTCIRCUIT PECULIAR THERETO AND A NEGATIVE POLARITY OUTPUT CIRCUIT COMMONWITH SAID FIRST RECTIFIER CIRCUIT, A VOLTAGE REGULATOR CIRCUIT INCLUDINGA SWITCHING TRANSISTOR HAVING AT LEAST EMITTER AND COLLECTOR ELECTRODESAND MEANS FOR CONNECTING SAID VOLTAGE REGULATOR CIRCUIT AND THE SERIESCOMBINATION OF SAID FIELD WINDING AND SAID EMITTER-COLLECTOR ELECTRODESOF SAID SWITCHING TRANSISTOR ACROSS SAID POSITIVE AND NEGATIVE POLARITYOUTPUT CIRCUITS OF SAID SECOND RECTIFIER CIRCUIT.